Vrchní, prchni! (1981)

It is the story of a man who had financial troubles. He was married several times and had to pay for several kids. He wanted to earn some extra money by playing in a cafe. But one drunken guest supposes he is a waiter and pays his bill to him. So the main hero finds his chance - he goes through restaurants, pretending that he is a waiter and asks people to hand their cash to him...